Concreto projetado é aquele pneumaticamente transportado e projetado a alta velocidade, sobre uma superficie, sendo auto-compactado. Assim, denota-se que suas propriedades são dependentes do processo de projeção utilizado. Desta forma, para se estudar o material, é importante ter-se o conhecimento do seu processo de produção (se por via seca ou úmida, equipamentos e mão-de-obra utilizados, etc.) e das propriedades especificas do concreto projetado (como a reflexão, o desplacamento e a liberação de poeira ou névoa) e as respectivas formas de controle. Foi executado o estudo experimental do concreto projetado via seca, onde foi possivel caracterizar algumas diferenças de comportamento em relação ao concreto convencional. Entre elas está o fato de que a maior compactação e resistência mecânica é obtida com o teor ótimo da mistura e não com a menor relação água/cimento. Constatou-se o fato da projeção do concreto no teto fornecer um material de melhor qualidade que aquele projetado na parede. Finalmente, para a obtenção de um material boa qualidade, é fundamental o controle rigoroso do teor de aditivo acelerador, a utilização de bicos afunilados, pressão de ar comprimido adequada, pré-umidificação com injeção de água sob pressão e seguir as recomendações para o controle da qualidade do processo de projeção como um todo. / Shotcrete is concrete pneumatically conveyed and projected at high speed onto a surface, compacting itself. Thus its properties depend on the shooting process. It is important to know the shooting process (wet ou dry-mix process, equipaments and working crew, etc.), the specific properties of shotcrete (rebound, sloughing and dust generation) and respective mean of controlo An experimental study was made using dry-mix shotcrete, where it was possible to point out some differences of the plain concrete analysis. One of these is the high compaction and stregth achieved with the optimum waterIdry materiaIs ratio and not the minimum water/cement ratio. Shotcrete, gunned in overhead, generates a better material compared to the vertical walls. Finally, to obtain a good quality material, it\'s very important to make a rigorous control of the accelerator admixture contento AIso, it is recommended to use a funnelshaped nozzle, adequate compressed air pressure, hidromix with high water pressure and to follow the recommendations on alI shotcreting process quality control.

Protection management with the aid of plant protection products makes it possible to carry out pest control programs in agricultural environments and make them less hazardous for the cultivation of products on a large scale. However, when these programs are put into effect, only a small proportion of the sprayed products is really deposited on the target area while much of it is carried to neighboring regions. The scientific literature includes studies on the use of mathematical techniques to calculate the physical transformation and movement and provide a deposition estimate of the product. On the basis of this prediction, it is possible to configure a system which can allow the spraying to be carried out in normal weather conditions in the region for a satisfactory performance, although these conditions can undergo changes and make any statistical configuration unreliable. An alternative way of overcoming this problem, is to adapt the spray elements to the meteorological conditions while the protection management is being undertaken. However, the current techniques are operationally expensive in computational terms, which makes them unsuitable for situations where a short operational time is required. This thesis can be characterized as descriptive and seeks to allow deposition predictions to be made in a rapid and precise way. Thus it is hoped that the new approaches can enable the spray element to be adapted to the weather conditions while the protection management is being carried out. The study begins by attempting to reduce costs through a computational model of the environment that can speed up its execution. Subsequently, this computational model is used for predicting the rate of deposition as a fitness function in meta-heuristic algorithms and ensure that the mechanical behavior of the spray element can be adapted to the weather conditions while the management is put into effect. The results of this approach show that it can be adapted to environments with low variability. At the same time, it has a poor performance in environments with a high variability of weather conditions. A second approach is investigated and analyzed for this scenario, where the adaptation requires a reduced execution time. In this second approach, a trained machine learning technique is employed together with the results obtained from the first approach in different scenarios. These results show that this approach allows the spray element to be adapted in a way that is compatible with what was provided by the previous approach in less space of time. / O manejo de proteção com uso de produtos fitofarmacêuticos possibilita o controle de pragas em ambientes agrícolas, tornando-o menos nocivo para o desenvolvimento da cultura e com produção em grande escala. Porém, apenas uma pequena parte do produto pulverizado realmente é depositado na área alvo enquanto a maior parte do produto sofre deriva para regiões vizinhas. A literatura científica possui trabalhos com o uso de técnicas matemáticas para calcular a transformação física e movimento para estimar a deposição do produto. Com base nessa predição é possível configurar o sistema de pulverização para realizar a pulverização sob uma condição meteorológica comum na região para um desempenho satisfatório, mas as condições meteorológicas podem sofrer alterações e tornar qualquer configuração estática ineficiente. Uma alternativa para esse problema é realizar a adaptação da atuação do elemento pulverizador às condições meteorológicas durante a execução do manejo de proteção. Contudo, as técnicas existentes são computacionalmente custosas para serem executadas, tornando-as inadequadas para situações em que é requerido baixo tempo de execução. Esta tese se concentra no contexto descrito com objetivo de permitir a predição da deposição de forma rápida e precisa. Assim, espera-se que as novas abordagens sejam capazes de possibilitar a adaptação do elemento pulverizador às condições meteorológicas durante a realização do manejo de proteção. Este trabalho inicia com o processo de redução do custo de execução de um modelo computacional do ambiente, tornando sua execução mais rápida. Posteriormente, utiliza-se este modelo computacional para predição da deposição como função Fitness em algoritmos de meta-heurística para adaptar o comportamento do elemento pulverizador às condições meteorológicas durante a realização do manejo. Os resultados desta abordagem demonstram que é possível utilizá-la para realizar a adaptação em ambientes com baixa variabilidade. Por outro lado, pode apresentar baixo desempenho em ambientes com alta variabilidade nas condições meteorológicas. Uma segunda abordagem é investigada e analisada para este cenário, onde o processo de adaptação requer um tempo de execução reduzido. Nesta segunda abordagem é utilizado uma técnica de Aprendizado de Máquina treinada com os resultados gerados pela primeira abordagem em diferentes cenários. Os resultados obtidos demonstram que essa abordagem possibilita realizar a adaptação do elemento pulverizador compatível com a proporcionada pela abordagem anterior em um menor espaço de tempo.

Made available in DSpace on 2014-06-11T19:22:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-12-20Bitstream added on 2014-06-13T19:48:28Z : No. of bitstreams: 1 rodrigues_acp_me_botfca.pdf: 540833 bytes, checksum: 242455721b1b2564e11f5e3a054529f2 (MD5) / O presente trabalho teve como objetivo avaliar a quantidade e qualidade da deposição da calda de pulverização em plantas de feijão, Bidens pilosa L. e de Brachiaria plantaginea (Link) Hitch, presentes na linha e entrelinha da cultura, além da deposição no solo, em aplicações de pós-emergência. Foi utilizado como traçador o corante Azul Brilhante FDC -1 na concentração de 500 ppm. Os tratamentos constituíram de 3 modelos de ponta de pulverização, jato plano (XR 110015 VS e XR 11002 VS), jato plano duplo (TJ60 11002 VS) e jato cônico (TXVS 6 e TXVS 8); e dois volumes de aplicação 150 e 200 L ha-1, respectivamente. Utilizou-se o delineamento em blocos ao acaso, com 4 repetições. Os resultados dos dados quantitativos de deposição foram analisados nos seguintes esquemas em fatorial: para os depósitos em plantas de feijão foi utilizado o esquema 3 x 2 (3 modelos de pontas de pulverização x 2 volumes de aplicação); para as plantas daninhas presentes na linha e na entrelinha da cultura do feijão, o esquema foi 3 x 2 x 2 (3 modelos de pontas de pulverização x 2 volumes de aplicação x 2 espécies de plantas daninhas); para as estimativas de deposição no solo, o esquema foi 3 x 2 x 2 (3 modelos de pontas de pulverização x 2 posições (linha e entrelinha) x 2 volumes de aplicação). Foram amostradas 25 plantas por repetição em cada parcela, tanto para as plantas de feijão quanto para as plantas daninhas presentes na linha e na entrelinha da cultura. Após a aplicação, as plantas foram imediatamente coletadas, e em seguida foram lavadas em 100 mL de água destilada para posterior quantificação do traçador em espectrofotômetro. Para as analises qualitativa, cada planta selecionada ao acaso dentro da faixa de aplicação da barra foi considerada uma repetição, o que representou um total de 100 repetições. Os dados obtidos foram... / The present work had as objective to evaluate the amount and deposition quality of spray solution in common bean plants, Bidens pilosa L. and Brachiaria plantaginea (Link) Hitch, current in the crop row and spacing row, beyond the deposition in soil, in applications of post-emergency. It was used the brilliant blue FDC - 1 as tracer solution, with 500 ppm. The treatments had constituted of 3 models of spray nozzles, flat fan nozzle (XR 110015 VS and XR 11002 VS), double flat fan nozzle (TJ60 11002 VS) and cone nozzle (TXVS 6 and TXVS 8); and two application volumes 150 and 200 L ha-1, respectively. It was used a randomized blocks design, with four replications. Being that, the results of the quantitative data of deposition had been analyzed in following factorial schemes: for the deposits in common bean plants was used 3 x 2 factorial scheme (3 models of spray nozzle x 2 application volumes); for the weeds in the common bean crop row and spacing row, the factorial scheme was 3 x 2 x 2 (3 models of spray nozzle x 2 application volumes x 2 weed species); for the soil deposition estimates, the factorial scheme was 3 x 2 x 2 (3 models of spray nozzle x 2 positions (row and spacing row) x 2 application volumes). Were sampled 25 plants for replication in each plot, as much for the common bean plants as current weeds in crop row and spacing row. After application, the plants were immediately collected, and after they had been washed in 100 mL of distilled water for posterior tracer quantification in spectrophotometer. For the quantitative analysis, each random selected plant inside of boom application stripe bar was considered a replication, representing a total of 100 replications. The obtained data had been adjusted a regression curve for Gompertz model. The results had evidenced that: (i) the biggest deposits of spray solution in soil had occurred in the crop spacing row, independent of the... (Complete abstract click electronic access below)

Orientador: Carlos Gilberto Raetano / Banca: Dagoberto Martins / Banca: Marcelo da Costa Ferreira / Resumo: O presente trabalho teve como objetivo avaliar o efeito da assistência de ar junto à barra de pulverização e três volumes de aplicação na dessecação e deposição da calda em arroz vermelho sob cultivo de nabo forrageiro em recuperação de áreas de várzeas, pulverizado com herbicida paraquat e corante azul brilhante, respectivamente. Os volumes de calda de pulverização foram 100, 200 e 300 L ha-1, da solução contendo corante alimentício (0,15%, p/v). Tanto na presença do ar junto à barra quanto na sua ausência foram utilizadas pontas de pulverização de jato plano tipo AXI 110015 a pressão de 117,3 kPa, AXI 11002 e AXI 11003 a pressão de 276 kPa. A avaliação da deposição da pulverização deu-se em folhas de plantas de arroz vermelho. Verificou-se nos resultados que houve diferença na deposição entre diferentes técnicas e volumes de calda testados nas plantas de arroz vermelho. Maior deposição foi alcançada pelo maior volume aplicado (300 L ha-1) com a assistência de ar junto à barra pulverizadora. Não se constatou diferença na deposição quando aplicados os volumes de 100, 200 e 300 L ha-1 sem assistência de ar e 200 e 300 L ha-1 com assistência de ar. As maiores porcentagens de dessecação de arroz vermelho foram constatadas com a aplicação de 300 L ha-1, tanto na presença quanto na ausência de assistência de ar junto à barra pulverizadora. / Abstract: The aim of this research was to evaluate the effect of air-assistance on spraying at three volumes in the dessecation and deposition on red rice under fodder radish cultivation. To evaluate the dessecation and spray deposition were used paraquat herbicide and a Brilliant Blue dye, respectively. The three volumes of spray were 100, 200 and 300 L ha-1, using a tracer dye at 0,15% (w/v). Both solution used flat fan nozzles AXI 110015 at 117.3 kPa, AXI 11002 and AXI 11003 at 276 kPa. The evaluation of deposition was made on red rice leaves. We observed no significant different deposition between spray techniques and application volumes on red rice plants. Higher deposition was obtained by 300 L ha-1 application with air assistance in the spray boom. No difference it was observed on spray deposition at 100, 200 and 300 L ha-1 volumes without air assistance and at 200 as well as 300 L ha-1 with air assistance. The highest percentages of red rice dessecation were observed with 300 L ha-1 application with or without air assistance at the sleeve boom sprayer. / Mestre

Made available in DSpace on 2017-07-10T17:37:27Z (GMT). No. of bitstreams: 1 Michele Aparecida Hartmann Schmidt.pdf: 230697 bytes, checksum: b08b482b200a54dcdc6e276a3ea6d3c2 (MD5) Previous issue date: 2006-09-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / To prevent the losses in agriculture has been the great objective of the Engineers Agronomists, as well as professionals of other similar areas of agrarian sciences that are worried very about the losses in agriculture, including the fitossanitária area. Most of the time, during the chemical control of plagues, harmful illnesses and plants, give to much importance to the fitossanitário product and little attention to the application technique. The consequence is the loss of effectiveness, when not total it failure of that take to the loss of yield of the cultivate and the damages to the environment and the proper health human being. The majority of the applications of agricultural defensives is made by means of spraying, that is, for the generation and emission of liquid particles. Due to those needs the present work was carried out in Cascavel PR, in the harvest 2004/2005, using the soybean cultivar CD 202, with the objective evaluating the amount of syrup deposited on the soybean leaves, varied the volume of syrup applied and the beaks types used in the spraying bar, used tracer substance, simulating the physical characteristics of the solutions of the products. To evaluate the spraying distribution, fifteen leaves were collected per plant in different extracts (higher, medium and lower), with the purpose of evaluating the syrup penetration, in agreement with the different beaks and applied volumes. The experimental design was arranged in randomized complete blocks, in factorial arrangement, with four beaks and point of the type simple fan, double fan, double fan with air injection and empty cone and 3 syrup volumes (150, 250 and 350 L ha-1). In agreement with the results obtained and in the conditions that the present work was carried out. In accordance with the results gotten and in the conditions where the present work was lead, concluded that: In what it says respect to the peaks of spraying in different extracts of the plants, can be concluded that, it did not have significant difference enters the used peaks in the experiment. As for the volumes of syrup volume, it did not have significant difference between the same ones, however when compared in different extracts of the plant, the biggest deposition L was gotten with the use of 250 ha-1, having been that when the volume for more varied or for less the deposition it was lesser. As for the extract of the plant, the deposition of syrup volume varied of decreasing form of the superior extract the inferior / Evitar as perdas na agricultura tem sido o grande objetivo dos Engenheiros Agrônomos, assim como profissionais de outras áreas afins de ciências agrárias que preocupam-se muito com as perdas na agricultura, incluindo a área fitossanitária. Na maioria das vezes, durante o controle químico de pragas, doenças e plantas daninhas, dá-se muita importância ao produto fitossanitário e pouca atenção à técnica de aplicação. A conseqüência é a perda de eficácia, quando não o fracasso total do tratamento, com superdosagens ou subdosagens, que levam à perda de rentabilidade dos cultivos e a danos ao ambiente e à própria saúde humana. A maioria das aplicações de defensivos agrícolas é feita por meio de pulverização, ou seja, pela geração e emissão de partículas líquidas. Diante dessas necessidades foi conduzido o presente trabalho foi conduzido no município de Cascavel PR, na safra de 2004/2005, utilizando o cultivar de soja CD 202, com o objetivo de avaliar a quantidade de calda depositada nas folhas da soja, variando-se o volume de calda aplicada e os tipos de pontas utilizadas na barra de pulverização, utilizando-se substância traçadora, simulando as características físicas das soluções de produtos fitossanitários. Para avaliar a distribuição da pulverização, foram coletadas quinze folhas por planta em diferentes extratos (superior, mediano e inferior), com a finalidade de avaliar a deposição da calda, de acordo com os diferentes pontas e volumes aplicados. O delineamento experimental constituiu-se de blocos ao acaso, em arranjo fatorial, compreendendo 4 pontas de pulverização com pontas do tipo leque simples, duplo leque, duplo leque com injeção de ar e cone vazio e 3 volumes de calda (150, 250 e 350 L ha-1 ). De acordo com os resultados obtidos e nas condições em que o presente trabalho foi conduzido, concluiu-se que: No que diz respeito às pontas de pulverização nos diferentes extratos das plantas, não houve diferença significativa entre as pontas utilizadas no experimento; no que se refere aos volumes de calda, não houve diferença significativa entre os mesmos, porém quando comparados nos diferentes extratos da planta, a maior deposição foi obtida com a utilização de 250 L ha-1, sendo que quando variou-se o volume para mais ou para menos a deposição foi menor. No que se refere ao extrato da planta, a deposição da calda variou de forma decrescente do extrato superior ao inferior

Le contexte du marché automobile actuel est conditionné par deux facteurs principaux : la prise de conscience del'impact sur l'écologie de ce mode de transport et une concurrence mondiale exacerbée. Ainsi, de nombreusesétudes soulignent l'intérêt de concevoir des moteurs dont le ratio puissance sur masse soit maximisé (Down Sizing).Ainsi les carters-cylindres traditionnellement réalisés en fonte pour des raisons de comportement tribologique sontreconçus pour être fabriqués à partir d'alliages d'aluminium. Ces derniers apportent un gain de masse au groupemotopropulseur mais présentent de piètres propriétés tribologiques. Pour pallier ce défaut, des chemises en fontesont généralement insérées dans les blocs lors de leur coulée. Toutefois cette solution n'est pas optimale et lesprocédés de projection thermique sont de plus en plus mis en oeuvre pour remplacer ces chemises par une mincecouche protectrice qui sera en contact avec les segments.Dans ce contexte ce travail se focalise sur l'application du procédé de projection thermique arc-fil rotatif pour ledépôt de revêtements en acier sur la paroi interne des fûts de carters-cylindres. L'objectif principal est de contribuerà cerner les mécanismes physiques reliant les paramètres de projection et les propriétés des revêtements. Desinvestigations ont été menées sur les différentes étapes de la vie des particules : les mécanismes d'atomisation ontété observés et quantifiés, les comportements à l'étalement des particules et les modes de refroidissement deslamelles ont été déterminés au moyen d'analyses des phases cristallines et les effets des paramètres opératoiressur la structure des dépôts ont été évalués. L'ensemble apporte ainsi de nouveaux éléments pour la maîtrise del'application de la projection thermique à l'arc-fil en milieu confiné et des pistes sont proposées pour optimiser lespropriétés des dépôts. / The current automotive market's context is conditioned by two main factors : the rising awareness of theenvironmental impact of this transportation mode and a strong competition between automakers at the world level.Thus, many studies already underlined the relevance of the « down sizing » of the engine blocks.Thus, cylinders-blocks, traditionally made from cast iron given its excellent tribological behavior and low cost, arenow designed with hypoeutectic aluminium-silicon cast alloys. However, the weight reduction brought by thesealloys is counteracted by their poor tribological properties. Therefore, Thermal spray processes are more and moresolicited to address this issue with the application of thin protective coatings on the working surfaces of thecylinders-blocks.In this frame, the present work was focused on the application of steel coatings on the bores' inner walls of cylinderblocks using the rotative twin-wire arc spray process. The main objective was to contribute to the understanding ofphysical mechanisms linking the spray parameters and the coating properties. Every stages of particles' life werethus investigated : the atomization mechanisms were observed and quantified, particles' spreading and coolingbehaviours were determined by mean of crystallographic examinations and process parameters' effects on coatingstructure were estimated. Globally, this document provides new elements contributing to the understanding and thecontrol of the process and solutions are proposed to raise the coatings properties.

This thesis develops analytical and numerical solutions that predict behavior of Cupric-Chloride droplets undergoing spraying and drying processes. Cupric-Chloride (CuCl2) is present as molten salt and slurry within the Copper-Chlorine thermo-chemical cycle for generation of hydrogen. Utilizing low-grade heat from nuclear or industrial sources to assist drying of Cupric-Chloride can increase efficiency of the overall process. Analytical correlations for heat and mass transfer are developed and applied to the analysis of a solution of Cupric-Chloride, subject to various drying conditions. The study provides new information on effects of different concentrations of water in CuCl2 slurry drying at low air temperatures. / UOIT

Solid oxide fuel cell compositionally graded electrolytes could offer the advantage of improving electrical performance and efficiency compared to single-layered or bi-layered yttria stabilized zirconia and samaria doped ceria electrolytes and improving mechanical performance by reducing thermal expansion mismatch stresses compared to bi-layered electrolytes with sharp interfaces. Manufacturing of these graded structures is difficult if implementing conventional wet ceramic techniques. Suspension plasma spraying is an emerging technology that has the potential to rapidly produce thin, dense ceramic layers with no requirement for post deposition heat treatments. However, SPS requires a careful examination of the stability of the feedstock suspensions in order to produce high quality coatings. Optimum suspension formulations with excellent particle dispersion were designed based on rheological and electrostatic stability measurements. These optimized suspensions were used as feedstocks for the fabrication of suspension plasma sprayed compositionally graded YSZ/SDC layers. The feasibility of fabricating graded electrolyte structures was thus demonstrated.

The reduction of manufacturing costs and the facilitation of direct-oxidation of hydrocarbon fuels have been identified as means of promoting the commercialization of the solid oxide fuel cell, a technology that offers both environmental and fuel conservation benefits compared to conventional energy conversion technologies. This research was conducted with the aim of realizing the production of direct-oxidation anodes using atmospheric plasma spraying, which has been identified as a fabrication technique that has the potential to reduce the manufacturing costs of solid oxide fuel cells. This thesis details the rationale behind the selection of the anode compositions (BaO-Ni-YSZ, CeO2-Ni-YSZ, and Sn-Ni-YSZ) and the specifics of the specialized fabrication strategy (SPS-SPPS) that was devised with the aim of realizing microstructures similar to those where the secondary phases (BaO, CeO2, and Sn) coat the surfaces of the primary Ni and YSZ phases. Results of XRD, SEM and EDS analyses are presented.

Solid oxide fuel cell compositionally graded electrolytes could offer the advantage of improving electrical performance and efficiency compared to single-layered or bi-layered yttria stabilized zirconia and samaria doped ceria electrolytes and improving mechanical performance by reducing thermal expansion mismatch stresses compared to bi-layered electrolytes with sharp interfaces. Manufacturing of these graded structures is difficult if implementing conventional wet ceramic techniques. Suspension plasma spraying is an emerging technology that has the potential to rapidly produce thin, dense ceramic layers with no requirement for post deposition heat treatments. However, SPS requires a careful examination of the stability of the feedstock suspensions in order to produce high quality coatings. Optimum suspension formulations with excellent particle dispersion were designed based on rheological and electrostatic stability measurements. These optimized suspensions were used as feedstocks for the fabrication of suspension plasma sprayed compositionally graded YSZ/SDC layers. The feasibility of fabricating graded electrolyte structures was thus demonstrated.